This research work was conducted in the fundo Miraflores, production and research at the Faculty of agricultural sciences of the National University of Sn Martin, located in the sector of Ahuashiyacu, Banda de Shilcayo district, province and Department of San Martín whereas with a forest ecosystem always seasonal green, in order to adapt and produce forage grasses and legumes in soil Ultisols of San Martin. The characteristics of the soil are: acid PH, low natural fertility and high concentration of aluminum. The experiment was carried out in a design of blocks totally at random, with arrangement of split plots; (with 12 treatments consisting of forage species (5) grasses and legumes (7) located in the plots and 4 ages, cutting (3, 6, 9 and 12 weeks) in the sub - plots). The phase setting, in a period of 4 months, indicates a good establishment in grass 5; heights of 60 to 80 cm between...